[NoteTwo or three 7.5-mm × 30-cm L21 columns may be used in place of the one 60-cm column, provided that system suitability requirements are met. The column temperature may be lowered to ambient temperature, although working at 40 provides stable separation conditions and ensures better sample solubility. ]

Standard solution: Transfer 15 mg of glycerin and 50 mg of tributyrin to a glass-stoppered, 25-mL conical flask. Add 3 mL of Propionating reagent, and heat at 75 for 30 min. Volatilize the reagents with the aid of a stream of nitrogen at room temperature, and add 12 mL of chloroform. Dilute 1 mL of this mixture with chloroform to 20 mL.

Sample solution: Transfer 50 mg of Glyceryl Monostearate to a glass-stoppered, 25-mL conical flask. Add 5 mL of Internal standard solution by pipet, and mix to dissolve. Immerse the flask in a water bath, maintained at a temperature between 45 and 50, and volatilize the chloroform with the aid of a stream of nitrogen. Add 3 mL of Propionating reagent, and heat at 75 for 30 min. Volatilize the reagents with the aid of a stream of nitrogen at room temperature, and add 5 mL of chloroform.